Gas Turbine Engine with Lifing Calculations Based Upon Actual Usage

ABSTRACT

A method of monitoring a gas turbine engine includes the steps of: (a) receiving information from actual flights of an aircraft including an engine to be monitored, and including at least one of the ambient temperature at takeoff, and internal engine pressures, temperatures and speeds; (b) evaluating the damage accumulated on an engine component given the data received in step (a); (c) storing the determined damage from step (b); (d) repeating steps (a)-(c); (e) recommending a suggested future use for the component based upon steps (a)-(d). A system is also disclosed.

BACKGROUND OF THE INVENTION

This application relates to a method and system for providing moreaccurate lifing estimates of components of a gas turbine engine basedupon actual usage, and further providing the ability to recommend futureuses to maximize the value of the remaining life.

Gas turbine engines are known and typically include a fan delivering airinto a compressor, where it is compressed, and then delivered into acombustor. The air is mixed with fuel and ignited. Products of thiscombustion pass downstream over turbine rotors, driving them to rotate.The turbine rotors, in turn, rotate the compressor and fan rotors.

As is known, a number of components in the gas turbine engine have auseful operating life or a published life which is limited due to thedamage accumulated on the components. As an example, the discs in thecompressor and a number of components in the turbine section havelimited lives. Regulatory authorities require a number of “cycles” beprovided (published) for each disk component per the applicableregulation(s). Operators of aircraft including the particular enginescount the number of flight cycles, and remove components for replacementonce the useful operating life or published life cycles has beenreached. The component lifing may include the impact of repairs toextend the useful life.

Typically, the cyclic lives for components have been set conservativelyand based upon one or a few design flight cycles. And all flights of allaircraft are counted as “one” cycle.

Each flight includes a speed increase at takeoff, which rapidly appliesstresses on the rotating parts. Then, there is climb which is alsorelatively high power, cruise at altitude which is relatively low power,and then landing and a thrust reverse to stop movement of the aircraft.

However, all flights are not equal. The damage accumulated on thecomponents is different for different flights.

SUMMARY OF THE INVENTION

In a featured embodiment, a method of monitoring a gas turbine engineincludes the steps of: (a) receiving information from actual flights ofan aircraft including an engine to be monitored, and including at leastone of the ambient temperature at takeoff, and the internal enginepressures, temperatures and speeds; (b) evaluating the damageaccumulated on an engine component given the data received in step (a);(c) storing the determined damage from step (b); (d) repeating steps(a)-(c); (e) recommending a suggested future use for the component basedupon steps (a)-(d).

In another embodiment according to the previous embodiment, theinformation received at step (a) is received remotely at a ground-basedevaluation location.

In another embodiment according to any of the previous embodiments, theinformation is streamed off of the aircraft to the ground-basedlocation.

In another embodiment according to any of the previous embodiments, theinformation is recorded substantially continuously during a flightonboard the aircraft, and received from the aircraft at a later time.

In another embodiment according to any of the previous embodiments, therecommended future use is replacement or repair.

In another embodiment according to any of the previous embodiments, therecommended future use includes a suggestion to utilize a particularcomponent or engine on a particular type flight.

In another embodiment according to any of the previous embodiments, theparticular type flight is on an engine having a different thrust ratingthan a current use of the component.

In another embodiment according to any of the previous embodiments, theparticular flight is for use on an aircraft flying routes havingdistinct different ambient temperatures.

In another embodiment according to any of the previous embodiments, acomponent other than the component being monitored is evaluated alongwith the component being monitored to identify the suggested future use.

In another embodiment according to any of the previous embodiments, thestoring of step (c) is supplemented to provide information on missingflights.

In another embodiment according to any of the previous embodiments, thesupplementation is provided by a conservative nominal predicted cycle.

In another embodiment according to any of the previous embodiments,actual flight data information is evaluated to develop algorithms thatcan then be utilized at step (b) to predict the actual damage on thecomponent being monitored.

In another embodiment according to any of the previous embodiments, amaintenance facility receives the suggested future use and takes anaction on the component.

In another embodiment according to any of the previous embodiments, theaction is reported back to be stored and utilized at least in step (c).

In another embodiment according to any of the previous embodiments,steps (a)-(e) are performed on an aircraft including the engine beingmonitored.

In another embodiment according to any of the previous embodiments, theengine component is an engine life limited part.

In another featured embodiment, a system has a ground-based evaluationsystem programmed to perform the following steps: (a) receivinginformation from actual flights of an aircraft including an engine to bemonitored, and including at least one of the ambient temperature attakeoff, and the internal engine pressures, temperatures and speeds; (b)evaluating the damage accumulated on an engine component given the datareceived in step (a); (c) storing the determined damage from step (b);(d) repeating steps (a)-(c); (e) recommending a suggested future use forthe component based upon steps (a)-(d).

In another embodiment according to the previous embodiment, therecommended future use is replacement or repair.

In another embodiment according to any of the previous embodiments, therecommended future use includes a suggestion to utilize a particularcomponent or engine on a particular type flight.

In another embodiment according to any of the previous embodiments, acomponent other than the component being monitored is evaluated alongwith the component being monitored to identify the suggested future use.

In another embodiment according to any of the previous embodiments,actual flight data information is evaluated to develop algorithms thatcan then be utilized at step (b) to predict the actual stress on eachparticular component being monitored.

In another embodiment according to any of the previous embodiments, anaction taken based upon the suggested future use is reported to theground-based evaluation system, stored and used at least in performingstep (e).

In another embodiment according to any of the previous embodiments,steps (a)-(e) are performed on an aircraft including the engine beingmonitored.

In another embodiment according to any of the previous embodiments, theengine component is an engine life limited part.

In another embodiment according to any of the previous embodiments, theevaluation system is ground based.

These and other features may be best understood from the followingdrawings and specification.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a number of possible flight scenarios.

FIG. 2 is a schematic of an aircraft and a monitoring system.

FIG. 3 shows steps in developing algorithms.

FIG. 4 shows the use of the developed algorithms in combination with theinformation gained from the FIG. 3 system.

FIG. 5A shows a first example engine.

FIG. 5B shows a second example engine.

DETAILED DESCRIPTION

FIG. 1 is a map showing the Americas. Three sample flights areillustrated. Flight A is in a cold environment and for a relatively longdistance. Flight B is over a shorter distance. Flight C is over adistance which is long and in a relatively hot area closer to theequator.

The prior art would assign the same amount of “damage”, one cycle, tolife limited components for each of Flights A, B, and C.

However, applicant has recognized that there may be greater damageaccumulated on aircraft engine components for the longer flights A and Cthan for the shorter flight B. This is because the aircraft typicallycarries greater weight and fuel. Thus, such flights use an engine thatdevelops a good deal more thrust. The greater thrust provides adifferent amount of damage to aircraft engine components than would bethe case for the flight B. Of course, these are examples only. A flightbetween continents could provide different damage accumulation.

In addition, the flight C in a relatively hot area may result in moredamage accumulation on aircraft engine components than would the flightA or B in relatively cooler areas.

As an example, temperatures within the gas turbine engine vary bymultiples of degrees for each increased degree in ambient temperature.Again, under the prior art, the effect of each of the flights would betaken conservatively and, thus, the lesser damage caused by a flightsuch as flight B would be “over credited” as against the life of anengine component.

FIG. 2 shows a system 90 for evaluating the remaining life forcomponents on an aircraft engine 100. As the aircraft operates anon-board data gathering system 102 gathers a good deal of relativeinformation relative to the operation of the aircraft. In particular,ambient temperature and temperature at several locations across theaircraft engine are taken. Moreover, the internal pressures and speedsassociated with each of the components are also all stored.

While FIG. 1 and the illustrated system take information from anaircraft to a ground based evaluation system 90, it is also contemplatedthat the system 90 could actually be included on the aircraft.

This information is transferred to a receiver system 104 which may be onthe ground. The transmission may be streamed off the aircraft in realtime to ground based systems. Alternatively, the information may be sentto the receiver 104 when the aircraft is on the ground.

The files from each flight are stored at 106 and provided to an analyticsystem 108, which will predict the effect of each flight on the expectedlife of each component. Lifing algorithms are provided to the analysissystem 108 from stored lifing algorithms 110. The lifing algorithms aredeveloped in a manner to be disclosed below.

The information from the analytic system 108 is provided to an enginepart lifing tracking system 112, which maintains all of the informationgathered for each of the components on each aircraft associated with aparticular aircraft operator. Further provided to the system 112 are theairline flights, including the hours and cycles for each aircraft alongwith the location for which the routes would be operated. As an example,step 114 would provide information with regard to flights that areacross a route between two locations which are typically cooler ascompared to locations which are typically hotter.

In addition, at 116, engine configurations are provided to the system112. System 112 maintains the status of each of the components on eachof the engines on each of the aircrafts operated by a particularairline. This would be as the engine was initially built and would beupdated as it is maintained. As an example, should replacement partssubstitute out a part on a particular engine, the storage system at 116would be updated and would provide the information to the system 112.

At step 118, a course of action can be suggested based upon remainingpart hours and the operating cycle on each component. This would allowan airline to monitor the operation of each of its engines and suggestchange out of parts to a particular engine on a particular aircraftflying a particular route at step 120. This can be transmitted to anairline or other maintenance entity at step 121. The suggested changemay then occur. Once a change does occur, that change is sent backthrough step 116 to update the information stored in system 112.

Of course, items 104, 106, 108, 110, 112, 114, 116 and outputs 118 and120 may be within a single computer.

As shown at FIG. 3, an initial step is to develop the lifing algorithmsfor step 110. The algorithms are developed using the design tool setanalyses of flights used in component design, real world data 122 or acombination thereof. Thus, real world flights are gathered at 122 andthe design tool set is utilized at step 124 to predict the relativeeffect of each of the real world flights on each of the particularcomponents. As can be appreciated, there are a number of components inany one gas turbine engine which have life limits that must be evaluatedbased upon such analyses.

The UBL acronym as found in the figures stands for “Usage Based Life.”

At step 126, algorithms are developed which can monitor the damageaccumulated in each component based upon the different operationalconditions the component may see throughout the flight. Algorithms aredeveloped for the effect of temperatures, pressure, speed, etc.Algorithms are developed based upon results obtained from the tool setused for design and analysis of the subject components. The developedalgorithms are subsequently validated by comparing the results from thealgorithm with those of the design and analysis tool set. The algorithmsperform the function of and therefore replace the design and analysistool set. However, since the algorithms likely have some compensationfor their small difference relative to the design tool set, the designand analysis tool set may be used directly in lieu of the algorithmsshould they be sufficiently economical or efficient to execute.

FIG. 4 shows subsequent step. Actual flight data from an engine to beevaluated is gathered at step 102 (see FIG. 2). A particular flight mayhave more or less damage accumulated on the components. At step 108, thelife assessment may then be made utilizing algorithms 114.

Notably, there may sometimes be “missing data” with regard to a flightor a flight portion. As an example, as airlines are moving to thissystem, it is possible that an engine may have already been in serviceprior to when the evaluation of this disclosure begins. Thus, therewould be a good deal of missing flight information. Secondly, it ispossible that the system may sometimes be inoperative or providesporadic data acquisition. There would be no need to impact the aircraftflying under such conditions, as there are ways to supplement missinginformation.

Finally, the algorithm usage may be limited to flights which are deemedwithin the calibration range of the algorithm. It may not be desirableto extrapolate algorithms without independent validation. Thus, a flightoutside the algorithm calibration range may require engineeringintervention to review and assess whether the algorithm should beexpanded, revised, replaced, or perhaps revise the range ofapplicability. As an example, a flight might occur between a pair ofcities for which no algorithm is appropriate.

There are a number of reasons there may be missing data. The means toaddress missing data may include, but may not be limited to, assumingone or a combination of using the following strategies:

One may utilize a conservative flight assumption. Alternatively,previous data recorded for the same or other airlines on the same orsimilar flight distances and ambient temperatures could be utilized.This could include a process by which the specific engine health wasincluded within the life assessment process. Alternatively, manual orautomatic intervention may be provided in which an analysis is performedusing either a design tool set, or an algorithm to understand complexinteraction. This may suggest a detailed engineering analysis in lieu ofthe disclosed algorithms.

The decision to use one or a combination of these options may depend onthe extent of missing data. If the amount of missing data is low, thenusage of a conservative flight assumption may be expedient andtechnically conservative. However, as increased data is missing, morecomplicated assessment processes become more viable and will likely leadto a smart algorithm process which appropriately fills the gaps withacceptable bits of knowledge for life processing.

Not only will more accurate evaluations of the effect of actual flightson an aircraft engine component be developed, but also suggestions maybe made to airline operators with regard to placement of particularcomponents to maximize the life of all of the components workingtogether on a particular engine. As an example, in FIG. 5A, an engine130 is shown. The fan 132 may have 12,000 cycles left. The low pressurecompressor 134 may have 12,000 cycles left. The diffuser 138, highpressure turbine 140, and low pressure turbine 141 may have 8,000 cyclesleft. Notably, the 8,000 cycles are available should the high pressureturbine be operated at 30,000 pounds thrust. The high pressurecompressor 136 has 4,000 cycles left.

Thus, this engine has 4,000 cycles left before it will requiremaintenance. The inventive method and apparatus may be utilized toensure that the operator is able to get at least 4,000 cycles from thehigh pressure compressor discs.

Further assume the high pressure compressor 136 is built with repairedblades or vanes that have only a 50 percent probability to reach 4,000cycles if run at 30,000 pounds thrust due to a known shortcoming of theparticular repair on some vanes. Thus, while we can assume the highpressure compressor discs may reach 4,000 cycles, there is a possibilitythat the repaired vanes in the high pressure compressor may not reach4,000 cycles.

As shown, a lifing algorithm has been developed for the high pressurecompressor. Its chances of not reaching 4,000 cycles are shown at curve142. Curve 142 assumes 35,000 pound thrust and in hot ambienttemperature conditions. On the other hand, the algorithm curve 144 wouldbe for 30,000 pound thrust and at colder ambient conditions. As can beseen, the probability of the high pressure compressor reaching the 4,000cycles is much greater if that particular component is utilized on anengine operating at the lower thrust load and in colder ambientconditions. Thus, a suggestion may be made to the airline to move thatengine to such a route and aircraft configuration.

FIG. 5B shows a second scenario 145. The fan 146 has 8,000 life cyclesleft. The low pressure compressor 148 has 8,000 cycles left. The highpressure compressor has 15,000 cycles if operated at 30,000 poundsthrust. The diffuser 152 has 4,000 cycles if operated at 30,000 poundsthrust. The high pressure turbine 153 and the low pressure turbine 154,respectively, each have 4,000 cycles at 30,000 pounds thrust.

Assume now that the high pressure turbine 153 is rebuilt with all newairfoils. If this turbine was placed on an engine that would be on anaircraft with lower thrust and in colder temperatures, there is a goodlikelihood that when the turbine discs reach their mandatory replacementlife, there will be a large amount of life left on the turbine airfoils.Thus, a recommendation may be made to the airline that this particularhigh pressure turbine be assigned to an aircraft for long flights and ina location with hotter ambient temperatures. Now, the high pressureturbine airfoils will likely be closer to their useful life when theengine must be scrapped or otherwise repaired.

As can be appreciated, the disclosed invention provides much moreaccurate evaluation of the actual remaining life on an aircraftcomponent.

In summary, a method of monitoring a gas turbine engine includes thesteps of (a) receiving 104 information from actual flights of anaircraft including an engine to be monitored, and including at least oneof ambient temperature at takeoff, internal engine pressures,temperatures and speeds; (b) evaluating the damage accumulated on anengine component 108 given the data received in step (a); (c) storing112 the determined damage from step (b); (d) repeating steps (a)-(c);and (e) recommending a suggested future use of the component 120 basedupon steps (a)-(d).

The information received at step (a) is received remotely at aground-based evaluation location. The information is streamed off of theaircraft to the ground-based location.

Alternatively, the information is recorded substantially continuouslyduring a flight onboard the aircraft, and received from the aircraft ata later time.

The recommended future use could be replacement or repair. Therecommended future use could alternatively include a suggestion toutilize a particular component or engine on a particular type flight.The recommended future use could be use on an engine having a differentthrust rating than a current use of the component. The recommendedfuture use could be use on an aircraft flying routes having differentaverage ambient temperatures than a current use.

A component other than the component being monitored may be evaluatedalong with the component being monitored to identify suggested futureuse.

In an embodiment, an engine subjected to this method after the enginehas already been in flight, and the effect of the earlier missingflights may be supplemented. The supplementation may be provided by aconservative nominal predicted cycle.

Actual flight data information 122 is evaluated to develop algorithms126 that can then be utilized at step (b) to predict the actual damageon each particular component being monitored.

A maintenance location, such as the airline, receives the suggestedfuture use, acts on it and sends update information about any changeback to the system performing steps (a)-(c) to be stored incorporatedinto step (e).

A system has an ability to receive data about actual flight conditionsfrom an aircraft at a ground-based facility. The system is programmedfor including (a) receiving information from actual flights of anaircraft including an engine to be monitored; (b) evaluating the damageaccumulated on an engine component given the data received in step (a);(c) storing the determined damage from step (b); (d) repeating steps(a)-(c); and (e) recommending a suggested future use for the componentbased upon steps (a)-(d).

It is known that the type of components having a limited cyclic life areknown as “engine life limited parts.” Generally, these are parts whichare difficult to contain should they fail. As such, there is arequirement that their life is limited to a particular number of cycles.In general, Chapter 5 “engine life limited parts” are rotating partswith full hoop geometry such as disks or rotating seals. On the otherhand, there are static parts which are also life limited and includedwithin Chapter 5. These Chapter 5 type parts are one classification ofcomponents being evaluated with the disclosed method, in preferredembodiments.

Of course, this disclosure may provide benefits in non-life limitedparts also. As examples, the engine components may include blades orvanes.

Although an embodiment of this invention has been disclosed, a worker ofordinary skill in this art would recognize that certain modificationswould come within the scope of this invention. For that reason, thefollowing claims should be studied to determine the true scope andcontent of this invention.

1. A method of monitoring a gas turbine engine comprising the steps of:(a) receiving information from actual flights of an aircraft includingan engine to be monitored, and including at least one of the ambienttemperature at takeoff, and internal engine pressures, temperatures andspeeds; (b) evaluating the damage accumulated on an engine componentgiven the data received in step (a); (c) storing the determined damagefrom step (b); (d) repeating steps (a)-(c); (e) recommending a suggestedfuture use for the component based upon steps (a)-(d).
 2. The method asset forth in claim 1, wherein the information received at step (a) isreceived remotely at a ground-based evaluation location.
 3. The methodas set forth in claim 2, wherein the information is streamed off of theaircraft to the ground-based location.
 4. The method as set forth inclaim 2, wherein the information is recorded substantially continuouslyduring a flight onboard the aircraft, and received from the aircraft ata later time.
 5. The method as set forth in claim 1, wherein therecommended future use is replacement or repair.
 6. The method as setforth in claim 1, wherein the recommended future use includes asuggestion to utilize a particular component or engine on a particulartype flight.
 7. The method as set forth in claim 6, wherein theparticular type flight is on an engine having a different thrust ratingthan a current use of the component.
 8. The method as set forth in claim6, wherein the particular flight is for use on an aircraft flying routeshaving a distinctly different ambient temperature than current use. 9.The method as set forth in claim 1, wherein a component other than thecomponent being monitored is evaluated along with the component beingmonitored to identify the suggested future use.
 10. The method as setforth in claim 1, wherein the storing of step (c) is supplemented toprovide information on missing flight information.
 11. The method as setforth in claim 10, wherein the supplementation is provided by aconservative nominal predicted cycle.
 12. The method as set forth inclaim 1, wherein actual flight data information is evaluated to developalgorithms that can then be utilized at step (b) to predict the actualdamage accumulated on said component being monitored.
 13. The method asset forth in claim 1, wherein a maintenance facility receives thesuggested future use and takes an action on the component.
 14. Themethod as set forth in claim 13, wherein the action is reported back tobe stored and utilized at least in step (c).
 15. The method as set forthin claim 1, wherein steps (a)-(e) are performed on an aircraft includingthe engine being monitored.
 16. The method as set forth in claim 1,wherein the engine component is an engine life limited part.
 17. Themethod as set forth in claim 1, wherein the suggested future use istransmitted to a maintenance facility.
 18. A system comprising: aground-based evaluation system programmed to perform the followingsteps: (a) receiving information from actual flights of an aircraftincluding an engine to be monitored, and including at least one of theambient temperature at takeoff, and internal engine pressures,temperatures and speeds; (b) evaluating the damage accumulated on anengine component given the data received in step (a); (c) storing thedetermined damage from step (b); (d) repeating steps (a)-(c); (e)recommending a suggested future use for the component based upon steps(a)-(d).
 19. The system as set forth in claim 18, wherein therecommended future use is replacement or repair.
 20. The system as setforth in claim 185, wherein the recommended future use includes asuggestion to utilize a particular component or engine on a particulartype flight.
 21. The system as set forth in claim 18, wherein acomponent other than the component being monitored is evaluated alongwith the component being monitored to identify the suggested future use.22. The system as set forth in claim 18, wherein actual flight datainformation is evaluated to develop algorithms that can then be utilizedat step (b) to predict the actual damage accumulated on each particularcomponent being monitored.
 23. The system as set forth in claim 18,wherein an action taken based upon the suggested future use is reportedto the ground-based evaluation system, stored and used at least inperforming step (c).
 24. The system as set forth in claim 18, whereinsteps (a)-(e) are performed on an aircraft including the engine beingmonitored.
 25. The system as set forth in claim 18, wherein the enginecomponent is an engine life limited part.
 26. The system as set forth inclaim 18, wherein said evaluation system is ground based.
 27. The systemas set forth in claim 18, wherein the suggested future use istransmitted to a maintenance facility.